Phase 4, Controlled Study in Adult Subjects Undergoing Primary, 1-2 Level, Open Lumbar Spinal Fusion Surgery

This is a Phase 4, multicenter, randomized, double-blind, controlled study in 38 adult subjects undergoing primary, 1-2 level, open lumbar spinal fusion surgery under general anesthesia. Subjects will be screened within 30 days prior to study drug administration and at least one day prior to surgery. During the screening visit, subjects will be assessed for past or present neurologic, cardiac, and general medical conditions that in the opinion of the Investigator would preclude them from study participation. After the informed consent form (ICF) is signed, a medical history, surgical history, physical examination, 12-lead electrocardiogram (ECG), vital sign measurements, select clinical laboratory evaluations, urine drug screen, alcohol breath test, and urine pregnancy test for women of childbearing potential will be conducted. Study drug, approximately 1-2 mL every 1.0-1.5 cm, will be administered using 20- or 22-gauge needles prior to wound closure. Administration Instructions/Procedures Study drug should be injected in the prescribed locations based on the areas of highest nerve density. Study drug will be administered using syringes with 20- or 22-gauge needles prior to wound closure. The Investigator must document the size of the incision. Each infiltration site should be spaced 1.0-1.5 cm apart and should deliver approximately 1-2 mL into both deep and superficial areas (para-spinous fascia, muscle, and subcutaneous layers). Total volume administered will be depended on the number of levels of dissection, as described below. Following infiltration, the tissue should visibly expand with minimal leakage. Total Volume of Expansion The Investigator must document the total volume used for each surgery. 1. Level Procedures Group 1: EXPAREL 266 mg in 20 mL + bupivacaine HCl 0.5% in 20 mL + 20 mL normal saline = total volume of 60 mL Group 2: Bupivacaine HCl 0.5% in 20 mL + 40 mL normal saline = total volume of 60 mL 2. Level Procedures Group 1: EXPAREL 266 mg in 20 mL + bupivacaine HCl 0.5% in 20 mL + 50 mL normal saline = total volume of 90 mL Group 2: Bupivacaine HCl 0.5% in 20 mL + 70 mL normal saline = total volume of 90 mL Drains may be used at the surgeon's discretion. In addition to LIA, all study participants will receive a standardized approach for managing postsurgical pain that includes a scheduled multimodal pain regimen including adjunctive analgesics, non-steroidal anti-inflammatory drugs (NSAIDs). Rescue analgesics will be available as needed. Postsurgical clinical assessments will include pain intensity scores using a 10-cm visual analog scale (VAS) (see Appendix 1); overall benefit of analgesia score (OBAS) questionnaire (see Appendix 2); total postsurgical opioid consumption; predefined opioid-related AEs; and nurse's satisfaction with overall analgesia (see Appendix 3). Adverse events will be recorded from the time the ICF is signed through Day 30. If a cardiac AE (e.g., chest pain \[angina, myocardial infarction\], abnormal/irregular heart rate \[bradycardia, tachycardia, extrasystoles\], or shortness of breath), neurological AE (e.g., altered mental status/altered sensorium, dizziness, dysarthria, hyperesthesia, metallic taste, peroral numbness, seizure, tinnitus, tremors, visual disturbance, muscular twitching or rigidity beyond 72 hours postdose, or tingling/paresthesia beyond 72 hours postdose), or serious AE (SAE) occurs during the study a 12-lead ECG, vital signs, and any appropriate clinical laboratory tests should be conducted. Postsurgical health economic outcome assessments will include hospital length of stay (LOS), use of skilled nursing facility, hospital readmissions, and use of other health services following discharge (phone calls related to postsurgical pain, unscheduled visits related to postsurgical pain, and visits to emergency department) through Day 30. A follow-up visit will be scheduled for all subjects on postsurgical Day 14. A follow-up phone call will be made on Day 30 to all subjects who received study drug to assess for adverse events (AEs). Number of Subjects (Planned): Approximately 194 subjects are planned for enrollment in this study in order to have at least 184 evaluable subjects.